Improved machine for cutting out grindstones



N. PETERS. PHOTO`LITHOGRAPHER, WASHINGTON. D c.

stent dtiljlirr.

JOSEPH E MITOHELL, OF PHILADELPHIA, PENNSYLVANIA.

Letters Patent No. 103,912, dated Jane 7, 1870.

`IMPROVJEID MACHINE FOR CUTTING OUT GRINDSTONES.

The Schedule referred to in these Letters Patent and making part of the same.

To all whom 'it 'may concern Be it known that "I, JOSEPH E. MITCHELL, of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain Improvement-s in `Machines for Cutting out Circular Stones; and I do hereby declare that the following is a t'ull, clear, and exact description thereof, reference being had to the annexed drawing making part of this speeification,in which- Y Figure 1 is a perspective view of my machine, constructed to cut out a series of stones at vone operation.

Figure 2 is ,a plan view of the plate, in which the the annular series of cutter-shafts have ltheir bearings, showing the radial slots to permit the shifting of such bearings and shafts.

'Figure 3 is a vertical section -of one of the cutters and its shaft.

The same letters are used in all the figures in the designation of identieai parts.

This invention relates to a machine foicutting or sawing'out griudstones, or other circular stones; and

My improvements consist in the combination and arrangement of various parts thereof; `as will more fully appear from thefollowing specification and claims.

'lo enable those skilled in the art to make and use my improvements, I will now proceed to describe their construction and operation.

In the annexed drawinge' p A represents a stout frame, consisting of a bedplate, upon which the stones to be ent are secured by clamps1 and uprights and eross-beams for the support of the operating mechanism.

B is a vertical shaft, arranged in the center of the frame so as to permit it to slide freely up and down.

It is revolved by means of a pulley or wheel, Bf, by any convenient power, such wheel being provided with a key fitting Iin a seat in the shaft, so that, although re-volving together, the latter may have the vertical movement above mentioned.

C is a disk of about the diameter of the stones to be cut out, and firmly secured to the lower portionof the shaft. y

Upon its periphery two or more downwardly-projecting cutters, O1, are fastened, and in its center it carries a drill, C?, which may be slightly longer than the cutters, so as to center the stones before the cutters begin to operate upon it.

Both cutters and drill I propose to armr with dia mond points upon their cutting-edges, to prevent their rapid wear. i

The drill I prefer to construct inthe form of a tube, slotted upon its lower end, as clearly-shown, so that it will cut a hole ot' the proper sizein the center of the grindstone, leaving a core.

D represents'a-,horizontal plate of cast-iron or other suitable material, secured to the uprights ofthe frame the proper distance above the bed-plate.

It has a central aperture, with bearing for the passage' of the shaft B, and a series of radial slots, D,

in which the bearings D2 are arranged, such bearings being made sufficiently long to give a steady support to the shafts which revolve therein.

The bearings consist of a flanged sleeve or box fitlting suuglyin the slots in the plate, in which they can-be secured at any desired point by a tighteningnut, D, screwed upon the end of the sleeve after it is passed through the slot, its flange abutting against the opposite side of the plate.

E E, 85o., represent a series of vertical shafts sliding freely up and down in the bearings D?, and provided, upon their lower ends, with cutter-heads El,

-cutters E2, and drills E3, similar, `in all respects, to

such parts as described in connection with the shaft B.

These shafts are driven by the centralshaft B through. the intermediate spur-wheel F on the latter, and spur-wheels G G on theformer, and, in order that all the shaft-sl may rotate at the same velocity, I propose-alwaysto use wheels of equal diameter upon all.

These wheels are supported upon the end of the bea-rings in the plate D, and are attached to their shafts by a feather and spline, as shown.

The operation of the machine may bedescribed as follows:

One or more slabs of stone having been sawed to the requisite thickness, are secured upon -the bedplate of the frame under the cutters which rest upon the upper one.

The central shaft B is then revolved at the proper speed, causing all the cutters to revolve in the same manner, and to gradually cnt up the stones under them into a numberof perfectly round stones, with eyes in their center, with the least possible waste.

The cutters, while operating on the stones, feed by their own weight and that ofthe lshafts to which they are attached, but if that is not suiiicient they may be further weighted.

Vater, or water and sand, must be supplied to the cutters in some convenient manner while thus operating.

Various sizes of circular f,stones can be cut out by this machine by vsimply removing the wheels and outters shown, and substituting larger or' smaller ones, and shifting the bearings D2 to suit the new conditions.

Vhen it is intended to cut stones without a central aperture, the drills are removed.

Having thus described my invention,

'What I claim, and desire t0 secure by Letters Patent isl. The combinatiou'of the shaft B with cutters 'C O1 G2, series of shafts E with similar cutters El E2 E3, and intermediate spur-wheels Fand G, substantially as and for the purpose set forth.

2. In combination with the shaft C and bearings D2, the radial slots D1 in the plate D, substantially as and for the purposeset forth.

Witnesses: J. E. MITCHELL.

FREDK. KA GEEL, A. P. Burana-FORD. 

